1. Field of the Invention
This invention relates to plastic propeller blades for electric marine trolling motors, and more particularly, to the modification of the plastic propeller blades to prevent weed entanglement thereof while in use.
2. Description of the Prior Art
There has been a problem with weeds entangling about the propeller and plastic blades of marine electric trolling motors. It is particularly a problem with certain types of weeds, such as peppergrass and eel grass, which tend to wrap around the hub and blades of the motor causing malfunctioning or complete stalling of the motor due to insufficient power to overcome the force of weeds entanglement. In order to restart the motor, the weeds must be removed. Sometimes this is done by reversing the rotation of the propeller and blades. In other instances, it requires pulling the motor out of the water and restarting it so as to fling off the weeds. In the most difficult circumstances, the weeds must be manually pulled off or cut off usually after removing the motor from the water.
Most of the marine electric trolling motors being manufactured and in the market place at the present time include propellers having a plastic hub with plastic blades. The manufacturers appear to use different types of plastic, such as ABS or Lexan. Most of the manufacturers advertise that their plastic propellers with plastic blades are weedless, that is, that they will operate in a weedy environment without the propeller becoming entangled by the individual weeds. Usually these weedless propellers include a central hub with 2 to 4 blades extending radially therefrom. It is stated by some manufacturers that the specific designs of their plastic propellers result in their propellers being weedless due to modifying the flow of the water so as to prevent entanglement of the weeds.
Based upon my observations these plastic propellers are not weedless when operating in waters containing peppergrass and eel grass. My views are based upon several years of experience of having used numerous models of marine electric trolling motors with plastic propellers and plastic blades from many manufactures while fishing either from my boat or from many other boats. To the best of my knowledge there is no marine electric trolling motor with plastic propeller and plastic blades in existence which will operate weedlessly when exposed to tough weeds similar to peppergrass and eel grass irregardless to their designs of the propellers and blades.
It is known in the prior art to protect the leading edges of turbine blades from erosion by modifying the blades with a more erosion resistant material.For example, U.S. Pat. No. 3,275,295 protects the leading edge of a steel turbine blade by forming a flat face on the blade with a cobalt chrome alloy bonded to a flat face formed on the blade. U.S. Pat. No. 4,808,055 restores the top of an eroded metal turbine engine blade with a metallurgically bonded wear resistant surface.
Although there is prior art directed to modifying turbine blades to prevent erosion, I am not aware of prior art directed to modifying plastic blades of propellers of marine electric trolling motors to prevent entanglement of weeds without reducing the efficiency of the operation of the propeller.